Rock drill



Feb. 21, 1933. w. H. MOSHER 1,898,639

ROCK DRILL Filed Aug. 19, 1930 EN TOR.

I 1 ."1 0 Hrs ATTORNEY.

Patented Feb. 21 1933 PATET mes WILLIAM H. MOSHER, OF EASTON, PENNSYLVANIA, ASSIGNOR TO INGERSCLL-RAND COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY ROCK DRILL Application filed August 19, 1930. Serial No. 476,314.

This invention relates to rock drills, but more particularly to fluid actuated rock drills of the type having a plurality of pistons adapted to reciprocate independently of each other and of the working implement intended to be actuated.

A few of the objects of the invention are to simplify the construction of rock drills of this type and to enable the ready assembly and disassembly of the parts thereof.

Other objects will be in part obvious and in part pointed out hereinafter.

In the drawing illustrating the invention and in which similar reference characters refer to similar parts,

Figure 1 is a sectional elevation of a rock drill illustrating one form which the invention may assume in practice and Flgure 2 is a sectional elevation of a rock drill showing a modification of the invention.

Referring to the drawing and at first more particularly to Figure l, A designates the cylinder element of a rockdrill which may comprise a pair of easing members or cylinders B and C having piston chambers designated D and E respectively and wherein are arranged reciprocatory hammer pistons F and G of the block type and lying wholly within their respective piston chambers.

The cylinders B and C may be centralized with respect to each other by forming a bore H in the rear end of the cylinder B to receive the forward end of the cylinder C.

A closure may be provided for the front end of the piston chamber D in the form of a front cylinder washer J having in this instance a bore K to receive slidably an an vil block L. The function of the anvil block L is to transmit the blows of the hammer pistons to a working implement O guided by a front head P which is seated on the front cylinder washer J whereby the cylin-' der B and the front head P are centralized with respect to each other.

Disposed within the bore H and forming a closure for the rear endof the piston chamber D is a valve chest Q, which may also serve .as a seat for the forward end of the cylinder G and forms a closure for the front end of the piston chamber The valve chest Q preferably comprises R and S of which one plate, as for instance a pair of plates the plate R, may be suitably recessed to form a valve chamber T adapted to accommodate a distributing valve U shown as being of v provided with a throttle valve chamber W I for the reception of a throttle valve X having a central bore Y into whichpressure fluid may be constantly conveyed from a suitable source of supply." In the wall of the throttle valve is aport Z to register with a passage 72 leading from the chamber Y to the valve chamber T.

Pressure fluid for the rear end of the piston chamber D is conveyed thereto by an inlet passage 0 in the plate R, and an inlet passage 03 in the plate R and the cylinder B conveys pressure fluid to the front end of the piston chamber D. Pressure fluid is conveyed to the rear end of the piston chamber B by an inlet passage 6 in the plate S and the cylinder C, and an inlet passage f in the plate S serves in a similar capacity for the front end of the piston chamber E.

The opposed end walls 9 and h of the valve chamber T serve as valve seats for the valve U which is shown tapered at each end from opposite sides to form a fulcrum on I the transverse median line of the valve and opposed wings j and k. The rear inlet passages 0 and 6 open from the seating surfaces g and h at one side of the'valve chamber T T and are controlled by the Wing of the valve U and the inlet passages d and f open from the valve seats 9 and h' at the opposite end of the valve chamber T and are controlled by the wing is of the valve U. Due to this forward end of one piston chamber and the rearward end of therother piston chamber to drive the pistons simultaneously in oppo site directions.

The cylinders B and C are provided with exhaust ports 0 and 39 respectively which may lead from the piston chambers directly to the atmosphere and are controlled in this instance by the pistons within the respective cylinders.

The anvil block L illustrated has a stem 9 which extends into the front end of the piston chamber D to receive blows of the piston F. In the present instance the stem 9 is provided with a rearward reduced extension 1* which extends through a. central bore 8 in the piston F and an aperture t in the valve chest Q into the front end of the piston chamber E to receive blows of the piston A. head a on the anvil block L cooperates with a shoulder 42 in the bore K to limit the distance which the stem 9 and the extension 1* may extend into the respective piston chambers.

In the form of the invention disclosed in Figure 2, the front cylinder washer J and anvil block L are both of substantially conventionaldesign, preferably disposed however, in an inverted position so that the head a, of the anvil blocl: is adapted to extend into the front end of the piston chamber Dto receive blows of the piston and the stem 9 seats upon the working implement O.

The means provided to transmit blows of the piston G to the working implement 0 comprises an anvil block '10 preferably arran ed coaxially with respectto the anvil blocK L and extending through the central bore 3 of the piston F to seat on the head a of theanvil block L. The rear end of the head a may be formed with depression as to receive the front end of the anvil block w for insuring centralization of tae anvil blocks L and w. The rear end of the anvil block to is shown extending through an aperture t in the valve chest Q and a bore y in a washer 2, shown occupying a position in the rearward portion of the bore H, into the forward end of the piston chamber E. The washer '2 forms closure for the forward end of the piston chamber E and serves to centralize the cylinders B and C with respect to each other. The bore 3 of the washer 2 preferably consists of a forward enlarged portion and a rearward reduced portion, thus forming a shoulder 2 which cooperates with the rearward surface of a collar 3 on the anvil block w for limiting the distance which the anvil block may extend into the piston chamber E. i

The operation of the device is as follows: Assuming the valve U to be in the position in which the wing y'th ereof is seated on the surface it and the wing is seated on the surface g, while the pistons F and G are in the rear and front ends respectively of the piston chambers D and E, pressure fluid entering the valve chamber Twill flow through the inlet passages 0 and f into the rear end of the piston chamber D and the front end of the piston chamber E. The introduction of pressure fluid into these ends of the piston chambers will cause the piston F to be impelled forwardly to deliver its blow to the working implement O and to impel the piston'G in the rearwardly direction. The strokes of the pistons F and G occur in exactly thesame time interval so that the shoe incident to the delivery of the blow of the piston F will be counterbalanced by the force of the piston against a body of air which will be compressed in the rear end of the piston chamber E.

During at least a portion of these movements of the pistons F and G the exhaust ports '0 and p will be covered by the pistons and air will be compressed in the forward end of the piston chamber D and rear end of the piston chamber E which will act through inlet passages e and d against the seated sides of the valve wings j and 7c tending to unseat the valve. Upon further movement of the pistons D and E the exhaust ports '0 and 19 will be uncovered by the pistons to exhaust pressure fluid from the cylinders and during such occurrence the pres sure of fluid in the valve chamber T will drop considerably so that the force of the compressed air acting against the seated sides of the wings of the'valve U will'pre ponderate over the force of live motive fluid in the valve chamber T acting uponthe surfaces of the valve exposed thereto and quick ly throw the valve to its other limiting position.

Upon the reversal of the valve U, the passage e will be uncovered by the wing j and the passage d will be uncovered by the wing is. In this position of the valve, pressure fluid will flow into the front end of the piston chamber D and the rear end of the piston chamber E. The fluid thus admitted will retract the piston F to its initial position and impel the piston G forwardly to deliver its blow against the anvil block whereby it will be transmitted to the working implement.

While the pistons are moving in these directions, the exhaust ports 0 and p will first be covered by the pistons thereby entrapping air in the rear end of the piston chamber-D and the front end of the piston chamberE which will be compressed and passing through the passages 0 and f will tend to unseat the valve U. As the pistons F and G continue on their strokes, they will uncover the exhaust ports 0 and p to permit exhaust of fluid from the piston chambers D and E and thereby cause a drop in the pressure of fluid in'the valve chamber T. The valve U will thereupon be urged to its initial position by the compressed fluid acting upon the seated sides of the wings of the valve.

If desired,provision may be made for the eliminating or materially reducing by well known means the volume of air compressed by the pistons on their working strokes to obtain a powerful blow of the pistons. In this event the distributing valve may be thrown solely by the action of air compressed by that piston which is travelling on its return stroke.

I claim:

1. A rock drill comprising a pair of coaxially arranged cylinders, reciprocatory hammer pistons in the cylinders and each piston lying wholly within its cylinder, a working implement, means for transmitting the blows of the pistons to the working implement, a valve chest interposed between the cylinders and forming a head for each of the cylinders, and a valve in the valve chest for controlling the distribution of pressure fluid to the ends of the cylinders for actuating the pistons.

2. A rock drill comprising a pair of coaxially arranged cylinders, a bore in one of said cylinders, a valve chest disposed in said bore and forming a head for said cylinder, reciprocatory hammer pistons in the cylinders, a valve in the valve chest controlling the distribution of pressure fluid to the ends of the cylinders for actuating the pistons, and means seated on the valve chest and extending into both cylinders to centralize the cylinders with respect to each other.

3. A rock drill comprising a cylinder element, means in the cylinder element forming a pair of piston chambers, a front head on the cylinder element, a working implement guided by the front head, a reciprocatory hammer piston in each piston chamber, an anvil block for transmitting blows of one of the pistons to the working implement, and an anvil block cooperating with thefirst said anvil block to form a path for the blows of the other piston to the working implement.

4. A rock drill comprising a cylinder element, means in the cylinder element forming a front and a rear piston chamber, a reciprocatory hammer piston in each piston chamber, a front head on the cylinder element, a working implement guided by the front head, an anvil block extending into the front piston chamber to transmit blows of the piston therein to the working implement, means extending into the rear piston chamber and cooperating with the first said anvil block for transmitting blows of the piston therein to the working implement, and means for limiting the distance which said anvil block and the last mentioned means may extend into the respectivepiston chambers.

5. A rock drill comprising a cylinder element, means in the cylinder element forming a front and a rear piston chamber, a front head for the cylinder element, a working imthe piston therein to the working implement,

and means on the last said anvil block for limiting the distance which said anvil blocks may extend into the respective piston chambers.

In testimony whereof I have signed'this specification.

WILLIAM H. MOSHER. 

